48 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



EXPLANATION OF PLATES 

 GENERAL STATEMENT 



To avoid unnecessary repetition, locality and collection numbers 

 are only indicated for the few illustrated specimens that are not 

 part of the writer's collection cs-4 from the North Chatham locality. 

 Three specimens (pi. 7, fig, 18; pi. 9, figs. 14-16; pi. 11, figs. 6, 7) 

 are from U.S.G.S. collection 4216 at the same locality. One specimen 

 (pi. 5, figs. 13, 14) was collected near Elgin Station, Quebec, 

 Canada. 



All figured specimens show the outer surface of the test. 



Plate 1 



Page 



Fig. 1. Calodiscus reticulatus Rasetti, new species 24 



Dorsal and lateral views of cephalon, X3. 

 Fig. 2. Acidiscus birdi Rasetti, new genus, new species 11 



Lateral and dorsal views of cephalon ; pygidium ; X2. 

 Fig. 3. Bathydiscus dolichometopus Rasetti. new genus, new species . . 17 



Dorsal, frontal, and lateral views of cephalon; posterior, lateral, and 

 dorsal views of pygdium ; X4. 

 Fig. 4. Oodiscus subgranulatus Rasetti, new genus, new species ... 29 



Dorsal, frontal, and lateral views of cephalon ; pygidium ; X4. 

 Fig. 5. Leptochilodiscus ptmctulattts Rasetti, new genus, new species . . 26 



Cephalon, X6. 



Plate 2 



Fig. 1. Serrodiscus suhclavatus Rasetti, new species 31 



Dorsal and oblique anterior views of cephalon; oblique posterior and 

 dorsal views of pygidium ; X4. 



Fig. 2. Analox bipunctata Rasetti, new genus, new species 15 



Dorsal and lateral views of pygidium ; lateral and dorsal views of 

 cephalon ; X6. 

 Fig. 3. Acimetopus bilobatus Rasetti, new genus, new species .... 14 

 Dorsal and lateral views of pygidium; oblique and dorsal views of 

 cephalon; X4. 



Plate 3 



Fig. 1. Bolboparia superba Rasetti, new genus, new species 19 



Dorsal and oblique views of cephalon, X4. 

 Fig. 2. Bolboparia elongata Rasetti, new species 20 



Pygidium, XS. 

 Fig. 3. Litometopus longispinus Rasetti, new genus, new species ... 27 



Dorsal and lateral views of cephalon ; pygidium ; X2. 



